The National League (NL) is a professional ice hockey league in Switzerland and is the top tier of the Swiss league system. Prior to the 2017–18 season, the league was known as National League A. During the 2018–19 season, the league had an average of 6,949 spectators per game which is the highest among European leagues (ahead of the KHL with 6,397 and the DEL with 6,215).

The National Basketball League (NBL) was a professional basketball league in the United States established in 1937. After the 1948–49 season, its twelfth, it merged with the Basketball Association of America (BAA) to create the National Basketball Association (NBA). Five current NBA teams trace their history back to the NBL: the Atlanta Hawks, the Detroit Pistons, the Los …

In 1920, an American football league was formed. It was called the American Professional Football Association. In 1921 it changed its name to the National Football League.In 1960 another league was formed, called the American Football League.In 1970 the National Football League and the American Football League joined together so that the teams from each league could …